Fabrication and luminescent properties of the core-shell structured YNbO4:Eu3+/Tb3+@SiO2 spherical particles

The core-shell structured YNbO4:Eu3+/Tb3+@SiO2 particles were realized by coating the YNbO4:Etr(3+)/Tb3+ phosphors onto the surface of spherical silica via a sol-gel process. The obtained materials were characterized by means of X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), transmission electron microscopy (TEM), Fourier transform IR spectroscopy (FT-IR), photoluminescence (PL) spectra, and cathodoluminescence (CL) spectra. The results indicate that 600 degrees C annealed samples consist of amorphous silica core and crystalline YNbO4: Re shell, having perfect spherical morphology with uniform size distribution. Upon excitation by UV or electron beam, these phosphors show the characteristic D-5(0)-F-7(1-4) emission lines of Eu3+ and the characteristic D-5(4)-F-7(3-6) emission lines of Tb3+. The PL intensities of Eu4+ can be tuned by altering the annealing temperature and the coating number of YNbO4:Eu3+ layers. (C) 2008 Elsevier Inc. All rights reserved.